Re: Emacs contributions, C and Lisp

From:

Perry E. Metzger

Subject:

Re: Emacs contributions, C and Lisp

Date:

Thu, 8 Jan 2015 19:51:48 -0500

On Thu, 08 Jan 2015 19:02:13 -0500 Richard Stallman <address@hidden>
wrote:
> > E.g., if it turns out that we
> > need 99% of what is already in the AST, the argument for using
> > it will be much more substantiated.
>
> For me, the concern is rather, what IS in the AST that we DON'T
> need.
I am sad to say that I can't think of something the compiler might
know that would not, at least some of the time, be very valuable to
an IDE to know as well. I say I am sad because it would be much
simpler to have this discussion otherwise.
We live in an era where people expect, more and more, to be able to
perform substantial source code to source code transformations using
programs. To restrict access to the AST is to declare that some such
transformations are to be impossible.
I recognize that you fear the use of GCC in proprietary systems, and
I recognize that this is a serious problem and legitimate concern. I
agree that it would be vastly preferable to get what programmers need
without opening up GCC this way.
However, as with the need to allow proprietary software to use GNU
libc and to allow proprietary software to run on GNU/Linux even though
it would be nicer to live in a world where that was not a practical
requirement, it is, de facto, likely to be necessary to allow such
breeches for the greater good of the free software movement.
In any case, LLVM will end up becoming the tool of choice for all
compiler writers -- has already, in fact, as I've said I've got
little choice about using it since GCC does not have the hooks into
the AST I need for my own compiler work -- and the question of
GCC's large share of the market will become impossible to defend
anyway.
Perry
--
Perry E. Metzger address@hidden